1. Field of the Invention
The present invention relates to a dangerous approach prevention device equipped in an own vehicle for preventing dangerous situations caused by approaching preceding vehicles.
Particularly, the present invention relates to a dangerous approach preventing device for preventing excessive approaches to preceding vehicles and collisions therewith by correcting a stopping force by operating a brake pedal after detecting distances from obstacles or preceding vehicles in a heading direction of the own vehicle.
2. Discussion of Background
Conventionally, a control device of detecting distances from obstacles or preceding vehicles in a heading direction and enhancing safety by correcting a braking pressure by a driver""s operation of a brake pedal to avoid collisions with the preceding vehicles is known as disclosed in JP-A-60-38238. Such a device is characterized that a right of controlling a braking force, namely priority over an own vehicle, is held by a driver, and operations by the driver are supported.
The conventional device disclosed in JP-A-60-38238 will be described in detail. The device is equipped with a radar apparatus for detecting following-on ranges and relative velocities from obstacles or preceding vehicles in a heading direction of the own vehicle, wherein safe following-on ranges are first operated based on the following-on ranges and the relative velocities when a brake pedal is manipulated. In the next, target acceleration necessary for keeping: the safe following-on ranges is obtained based on the following-on ranges and the relative velocities. Simultaneously, actual acceleration of the own vehicle is obtained based on a braking pressure caused by a manipulation of the brake pedal by the driver. As a result of comparison between the target acceleration and the actual acceleration, in case that the actual acceleration does not reach the target acceleration, the braking force is increased for correcting by pressurizing the braking pressure to bring the actual acceleration closer to the target acceleration.
According to the structure, in case that the brake pedal is stepped under a situation that a safe following-on range is not secured, when a sufficiently large braking pressure is indicated by the driver, a braking force based on the braking pressure is generated, and when a sufficiently large braking pressure is not indicated by the driver, the braking pressure is corrected to be pressurized to an appropriate level in order to increase a braking force. In case that the safe following-on range is secured at a time of manipulating the brake by the driver, the braking pressure is not thoughtlessly corrected and a driver""s feeling is not unreasonably spoiled. Thus, the own vehicle is always stopped with appropriate acceleration enabling prevention of collisions with preceding vehicles.
However, in the above-mentioned conventional device, the target acceleration of the own vehicle necessary for securing the safe following-on ranges is obtained based on only following-on ranges and relative velocities; and actual acceleration is corrected to bring it into the target acceleration, whereby the driver""s feeling does not always match with control of the vehicle. Specifically, when a case that a preceding vehicle is accelerating and a case that a preceding vehicle is decelerating are compared under a situation of same following-on ranges and same relative velocities, a risk of colliding with the preceding vehicle is less in the case that the preceding vehicle is accelerating. Therefore, corrections to same braking forces without consideration of acceleration and deceleration of preceding vehicles do not always satisfy drivers.
Further, in case that a driver intends to approach obstacles or preceding vehicles in a heading direction of an own vehicle or to pass preceding vehicles by changing to neighbor lanes, the conventional device works to correct the braking force of the vehicle to resultantly disturb driving by the driver.
It is an object of the present invention to solve or reduce the above-mentioned problems inherent in the conventional technique and to provide a dangerous approach prevention device which takes information of not only following-on ranges from obstacles or preceding vehicles in a heading direction of an own vehicle and relative velocities between the preceding vehicles and the own vehicle but also that of acceleration and deceleration of the preceding vehicles in, corrects a braking force of the own vehicle using the amount of correction obtained based on the information, and stops to correct the braking force when the driver intentionally approaches to the preceding vehicles, whereby driver""s feeling by the driver is not spoiled, and an excessive approach to the preceding vehicles and collisions with these are avoided for increasing safety.
According to a first aspect of the present invention, there is provided a dangerous approach prevention device for preventing danger caused when an own vehicle approaches to preceding vehicles, comprising: an unconsciousness judging means for detecting a condition that a driver does not consciously drive by dozing-off or the like and judging an unconsciousness in response to the detected condition, and a braking force adjusting means for adjusting a braking force of the own vehicle in response to a degree of approach to the preceding vehicles when the unconscious condition is detected and applying a braking force corresponding to an ordinary amount of stepping a brake pedal.
According to a second aspect of the present invention, there is provided the dangerous approach prevention device according to the first aspect of the present invention, wherein the degree of approach to the preceding vehicles is an approach index representing a level of inducing danger with respect to the preceding vehicles; and the approach index is derived based on selected data among a target following-on range, acceleration of the own vehicle, acceleration of the preceding vehicles, relative velocities, actual following-on ranges, and so on.
According to a third aspect of the present invention, there is provided the dangerous approach prevention device according to the second aspect of the invention, wherein the approach index is a time for colliding with the preceding vehicles, target acceleration of the own vehicle for running with safe following-on ranges from the preceding vehicles, or a result of comparison between the target acceleration of the own vehicle for running with the safe following-on ranges from the preceding vehicles and actual acceleration of the own vehicle.
According to a fourth aspect of the present invention, there is provided the dangerous approach prevention device according to the second or third aspect of the invention, wherein the actual acceleration of the own vehicle is derived from a velocity of the own vehicle or acceleration in response to the amount of stepping the brake pedal.
According to a fifth aspect of the present invention, there is provided the dangerous approach prevention device according to any one of the second through fourth aspects of the invention, wherein the relative velocity is derived from the following-on ranges or detected by a relative velocity sensor.
According to a sixth aspect of the present invention, there is provided the dangerous approach prevention device according to any one of the first through fifth aspects of the invention, wherein, in case that the driver is in an unconsciousness condition, the braking force adjusting means adjusts a braking force in response to a target braking force derived from the degree of approach, in response to the target braking force derived from the amount of stepping the brake pedal and the degree of approach, or by a predetermined target braking force based on the degree of approach.
According to a seventh aspect of the present invention, there is provided the dangerous approach prevention device according to any one of the first through sixth aspects of the invention, wherein the unconsciousness judging means is a dozing detecting means which judges unconsciousness upon detection of dozing-off of the driver, a means for detecting looking-aside which judges the unconsciousness when it is detected that the driver looks aside, a means for detecting driver""s intention of changing lanes which detects driver""s intentions of changing lanes and judges the unconsciousness in response to these intentions, or a means for judging the unconsciousness using a plurality of these three means arbitrarily selected which judges based on a logical product or a logical sum of the judgements of the unconsciousness.
According to an eighth aspect of the present invention, there is provided the dangerous approach prevention device according to any one of the first through seventh aspects of the invention, further comprising: a consciousness judging means which judges that the driver is not unconscious by detecting driver""s intentions of accelerating, wherein
the braking force adjusting means controls using an ordinary braking force in response to judgement that the driver is not unconsciousness.
According to a ninth aspect of the present invention, there is provided the dangerous approach prevention device according to the seventh aspect of the invention, wherein the dozing detecting means detects dozing-off of the driver based on a steering angle, a degree of changing the steering angle, or a frequency of changing the steering angle.
According to a tenth aspect of the present invention, there is provided the dangerous approach prevention device according to the seventh aspect of the invention, wherein the dozing detecting means is a means for detecting dozing-off based on directional changes of the own vehicle obtained by a gyro sensor, a means for detecting dozing-off based on lateral acceleration of the own vehicle, or a means for detecting dozing-off based on a lateral position of the own vehicle with respect to a driving lane thereof.
According to an eleventh aspect of the present invention, there is provided the dangerous approach prevention device according to the seventh aspect of the invention, wherein the dozing detecting means or the looking-aside detecting means detects dozing-off of the driver based on an image of a face of the driver shot by a camera.
According to a twelfth aspect of the present invention, there is provided the dangerous approach prevention device according to the seventh aspect of the invention, wherein
the dozing detecting means or the lane changing intention detecting means operates radiuses of road or curvature based on shapes of a lane and radiuses of road or curvature of a driving lane of the own vehicle based on a velocity and a steering angle of the own vehicle, and detects dozing-off or lane changing intentions in response to a comparison between results of these operations.
According to a thirteenth aspect of the present invention, there is provided the dangerous approach prevention device according to the seventh aspect of the invention, wherein
the lane changing intention detecting means is a means for judging driver""s intention of changing lane in response to a steering angle manipulated by the driver, a degree of changing the steering angle, or a frequency of changing the steering angle or a means for judging driver""s intention of changing lanes in response to a lateral position of the own vehicle with respect to a lane.
According to a fourteenth aspect of the present invention, there is provided the dangerous approach prevention device according to the seventh aspect of the invention, wherein the lane changing intention detecting means judges that the driver has an intention of changing lanes when a turn indicator light indicates a direction.
According to a fifteenth aspect of the present invention, there is provided the dangerous approach prevention device according to the eighth aspect of the invention, wherein
the accelerating intention detecting means is a means for detecting driver""s intention of accelerating based on the amount of stepping an accelerator pedal, a degree of change of stepping the accelerator pedal, or a frequency of change of stepping the accelerator pedal or a means for detecting driver""s intention of accelerating in response to changes to lower gears in a transmission and the amount of stepping the accelerator pedal.